Unlike most boy bands, 5 Seconds of Summer has no use for winking euphemisms

The members of One Direction have done important work in relaxing what’s expected of a boy band. They don’t dance. They often dress like hobos. And their music generally relies less on syrupy R&B grooves than on rowdy pop-rock guitars.

Onstage last August at Staples Center, where the British group played four sold-out concerts, they seemed so cheerfully indifferent to the arena-show enterprise that you wondered whether they knew anyone had turned up to watch them.

In at least one way, though, One Direction adheres to established boy-band orthodoxy: When they sing about sex, they do so via winking euphemism and thinly veiled double entendre.

“Let’s take a ride out in the cold air,” they sang on last year’s “Midnight Memories” album. “I know the way / Why don’t you go there with me?”

For a more direct approach to the topic, one must turn to 5 Seconds of Summer, the Australian boy band that opened those Staples gigs (and will do the same job when One Direction stops at the Rose Bowl in September).

The title of the group’s breakout hit, “She Looks So Perfect,” seems chaste enough, like a companion to One Direction’s ingratiating “What Makes You Beautiful” or maybe a spiritual sequel to “I Saw Her Standing There” by the original boy band.

Nope.

“You look so perfect standing there,” frontman Luke Hemmings sings over slashing power chords, “in my American Apparel underwear.” Later in the song he makes certain we can visualize the image, rhyming “mixtape straight out of ’94” with “your ripped skinny jeans lying on the floor.”

5 Seconds of Summer: 'She Looks So Perfect'

Watch the music video for 5 Seconds of Summer's "She Looks So Perfect."

Watch the music video for 5 Seconds of Summer's "She Looks So Perfect."

Here, finally, is an expression of teenage desire unmoored from any concern over plausible deniability.

Plenty more of those crop up throughout 5 Seconds of Summer’s self-titled debut, which came out Tuesday and shot instantly to No. 1 on the iTunes album chart.

“Everybody wants to take you home tonight / But I’m gonna find a way to make you mine,” Hemmings promises in “Don’t Stop,” while “18” depicts an older girl with “a job in the city” and “a naughty tattoo in a place that I wanna get to.”

And then there’s “Good Girls,” in which the singer declares that “good girls are bad girls that haven’t been caught.” Actually, in a rare show of strategic thinking, Hemmings presents that pearl of wisdom not as his own but as something a (presumably bad) girl revealed to him after he found her sneaking out of her bedroom window. The delight in his voice, though, is plain to hear.

Hemmings and his bandmates match these frank admissions with music that’s equally straightforward. Where recent boy-band predecessors such as the Jonas Brothers continually sought to expand their sound -- even One Direction put a Mumford & Sons-style folk number on “Midnight Memories” -- 5 Seconds of Summer sticks to crunching, tuneful pop-punk that pulls unabashedly from Blink-182, the English band Busted and, of course, Green Day, whose music Hemmings describes making out to in “Long Way Home.”

Sometimes the guitars come sweetened with synths, as in “Kiss Me Kiss Me”; occasionally the drums feel like they’ve been fed through a machine, as in “Beside You.” But the music moves with a consistent propulsion that minimizes whatever differences those sounds might have provided.

Indeed, you get a sense of these guys’ flattened-out worldview in “End Up Here,” where Hemmings recalls how his Kurt Cobain shirt attracted a girl who went on to tell him how much she loves “Livin’ on a Prayer” by Bon Jovi. (After that, naturally, they go back to her place.)

In ancient times, rock fans flattered themselves by distinguishing Nirvana from Bon Jovi; they consciously aligned themselves with one or the other. For 5 Seconds of Summer, though, that’s a dichotomy as false as a song about dancing that’s not really about dancing. If it rocks, they reason, what’s the problem?

Inevitably, the album closes with a ballad, the lovely “Amnesia,” about how the singer wishes he could “forget about the stupid little things” that led him to fall for an ex. But even when the tempo slows and the textures soften, Hemmings doesn’t abandon his dedication to teenage vérité.

“I drove by all the places we used to hang out getting wasted,” he sings, “I thought about our last kiss, how it felt, the way you tasted.”

Perhaps he was helped along in those uninhibited lines by one of the song’s co-writers, Sam Watters, a boy band veteran himself from his early-'90s days in Color Me Badd.